The invention relates to a transfer device in a transfer press or similar metal-forming machine.
Reference is made to the below listed related U.S. patent applications:
(i) U.S. application Ser. No. 07/413,607, filed Sept. 28, 1989, based on German Application No. P 39 05 073.4 filed in Germany on Feb. 18, 1989 33985; and
(ii) U.S. application Ser. No. 07/428,587, filed Oct. 30, 1989 based on German Application No. P 39 05 069.6 filed in Germany on Feb. 18, 1989 33987.
Transfer presses, bulky-part transfer presses, press installations are metal-forming machines, in which sheet metal parts are deformed by process steps, such as drawing and punching. For this purpose, the presses have at least one slide, at which a tool or a tool set (upper tool) is fastened which cooperates with a tool or tool set (lower tool) in the press bed or on a sliding table. The slides can be moved up and down by means of driving devices of the press. Intermediate depositing devices are mounted in areas between the frames leading to presses arranged behind them, these areas being known as idle stages. The changing of the tools or tool sets takes place utilizing of sliding tables which, for this purpose, can be moved into and out of the press.
In U.S. Patent Specification (US-PS) 4,625,540, a press is disclosed having a device for transferring sheet metal parts between working stages. This transfer device has two moving rails on both sides of the slide and tools and extending in conveying direction of the sheet metal parts. The moving rails are supported on the press bed by supports. In addition, a plate is provided for each moving rail, having rollers for placement on the moving rails. Both plates are connected with one another by a strut. Two transfer rods are disposed at the strut which extend in parallel with respect to the moving rails. The transfer rods are connected with a cam follower lever which receives a swinging motion from a control cam. On the side of the drive, the control cam is operatively connected with the main drive of the press. The transfer rods are rigidly connected with one another by traverses.
In guides of the transfer rods, cross bars are arranged which by means of an additional drive can be moved relative to the transfer rods. Vacuum suction devices are mounted at the cross bars which, by means of the movement of the cross bars, can be adjusted to the length of the sheet-metal parts. For the deforming stage, the cross bars with the vacuum suction devices can be adjusted into areas outside the slides and the tools. The transfer rods can be lifted and lowered by means of lifting devices which are not shown or explained in detail. The setting-up of the vacuum suction device with respect to the changed size of new sheet metal parts during the retrofitting of the press must take place manually without the possibilities of prior setting-up during the operating of the press
Accordingly, it is an object of the present invention to provide a transfer device which permits a changing operation of the holding devices to accommodate sheet metal parts of different sizes. In particular, the changing operation of the holding devices takes place automatically and at the same time with the change of the tools via a sliding table arrangement. The changing position of the holding devices or the devices carrying these holding devices is achieved independently of the drive for the transfer movements of the sheet metal parts.
Preferred embodiments of the present invention have a low-mass construction which is advantageous. The driving devices and the devices of the transfer device which transfer and deflect the movements are assigned to the area (head area) of the press or presses, in which the driving devices for the slide or the slides are also housed. The transfer device can be retrofitted in press trains as well as in compact presses. Other advantages of preferred embodiments of the present invention are the short transfer movements of the carriages and their temporary waiting position outside the working stages during the deforming phases.
In a particularly advantageous manner, the transfer device according to preferred embodiments of the present invention can be used in a new type of hybrid press installation with intermediate depositing devices set up between two working stages (idle stages) because the carriages, in pairs, can carry out different movements if the drive is designed correspondingly. The sandwich construction particularly of the carriages and the traverses not only permits the fastest possible adaptation to new sheet metal sizes and other sheet metal shapes, it also allows the simple removal and replacement of components and subassemblies.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.